Cartridge for an electronic pen



FIG. 1 is a top-right-rear perspective view of a representative embodiment of a cartridge for an electronic pen according to our new design;

FIG. 2 is a bottom-left-rear perspective view thereof;

FIG. 3 is a right-side elevational view thereof, wherein the left-side elevational view is a mirror image of the right-side elevational view; and,

FIG. 4 is a rear elevational view thereof.

The dashed broken lines in the drawings show portions of the cartridge for an electronic pen that form no part of the claimed design. 

CLAIM The ornamental design for a cartridge for an electronic pen, as shown and described. 